Feeding containers such as a baby bottle having a flexible nipple are used to feed infants, children, or adults with milk, formula, juice, semi-fluids and other fluids. A typical bottle has an open upper end that is threaded for engagement of a ring, which attaches the nipple to the open end. The nipple is coupled to the open end of the bottle by way of the ring. A cap is coupled to the top of the ring. Further, in some cases feeding containers comprise vent systems to enable air flow into the feeding container.